Centrifugal pump



Aug. 7, 1928.

J. K. MOINTYRE csrmrruaAL Puur P1106 Sept. 23, 1928 lle.

' www-0R H134 1mm:A

Patented Aug. 7, 1928.

UNITED STATES PATENT OFF JAMES K'. MCINTYRE, oF EA COMPANY, oF JERSEY CI This invent pumps and ino I C E STON, `PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RAND TY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

CENTRIFUGAL PUMP.

Application filed September 23, 1926. Serial No. 137,297. l

ion relates to centrifugal re particularly to pumps for liquids, operating at extremely low suction pressures.

The invention has for its object to .iu-

crease the efiici ency of a two stage centrifugal pump in which the suction pressure is extremely low,

pact arrangement of inlets and outlets for to provide a relatively comthe various stages and furthermore to balance the end thrusts of' the various stages effectively.

The invention will be more completely understood by re scription of an embodiment of ference to the fol owing dethe invention shown in the drawing.

In the drawing a centrifugal pump einbodying the invention is shown in longitudinal vertical section.

Referring to of the pump is part A being the drawing, the outer casing Shown in two parts, the lower provided with a base B and bearing supports C for the drive shaft D. The end bearings E may beof any suitable description. ing is adapted manner to the parts A 'and F which, with and glands K from the casin The upper part F of the casto be attached in any suitable lower part A and the two together form stuffing boxes suitable packing material H prevent the escape of liquid The pump in this instance is of the two stage type,

there being provided a first stage wheel L and a second or high pressure stage wheel O bot-h driven and supported by the single shaft D The Ypump is designed to operate at a high vacuum in the suction pipe. 'or this reason the first stage Wheel L is provided with thermore, the

large inlets P in order that' the velocity set up be relatively low. Furoutlet openingseQf from the relatively large and the diameter of the wheel is relatively small in order that the peripheral, relative and absolute velocities be kept low. In this stage the pump is de signed to bring the discharge pressure up to, at least, the atmospheric pressure.

The second wheel or impeller O is provided with a relatively small inlet R and discharge openings S in the usual manner.

Since there `is a slight positive pressure on its inlet the impeller can be designed for its maximum eflciency. As above described the two impell ers L and O differ radically operates with a slight pressure at its inlet.'

Since approximately one third of the work is done in the first 'impeller of the two stage pump and since its efficiency is somewhat low on account of the necessity of providing over-size openings and further since approximately two thirds of the work is done in the second or high efficiency impeller, the overall eflciency of the unit is increased over that which is to be expected from a pump having two similar impellers.

The inlet T for the first stage is located in the casing between impellers L and The passage U inlets P is formed by webs with the upper and lower parts F and A respectively of the casing, which also-serves as a partition forming part of the discharge passage leading to the second stage impeller O. The inlet and discharge passages, therefore, intertwine into a compact arrangement which can very conveniently be situated between the two impellers L and O. The second stage impeller is surrounded by a passage WV leading to a discharge opening X for connection with a suitable delivery pipe.

The shaft D may be provided with. a suitable tlange Y for connection with a convenient source of power for rotating the impellers L and O.

It will be noted that since the outer end faces of the impellers L and O are opposed to each other, and since the pressure on the back of' the high pressure impeller O is approximately twice the pressure on the back of the low pressure impeller L and further since the unbalanced area of the high pressure impeller O is approximately one-half the unbalanced area of the low pressure impeller L, the tendency toward axial thrust in the individual impellers acts in opposite directions and hence are neutralized.

claim:

1. A two stage centrifugal pump comprising a casing, a pair of impellers having inlets opposed to each other, the first stage impeller inlets being larger than the second stage impeller inlets and the first stage iinpeller being of less diameter than the second stage impeller.

2. A two stage centrifugal pump comprising a pair of impellers having their inlets combining in such a manner as to produce opposed to each other, a casing forming ina high overall eiliciency and a single shaft let and dischargepassages for the first stage for driving and supporting said impellers.

impeller intertwlned between the two 1m- 3. A two stage centrifugal pump having 5 pellers, the first stage impeller being provida pair of impellers with op osed inlets, the

ed with relatively large inlet openings difirst stage impeller being o lesser diameter reeted axially and arranged to operate at and having a greater unbalanced area than low fluid velocities and somewhat low eithe second stage impeller to neutralize the ciencv and said second stage impeller being axial thrust of the individual impellers.

lo provided with relatively small inlet openings In testimony whereof I have signed this and arranged to operate at high fluid vespecification.

locity and high eiiicieney, the two efficiencies JAMES K. MGINTYRE. 

